7 Things to Know Before You Donate Blood

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After the shooting in Las Vegas and other recent disasters, blood donations are in high demand. Here's what a doctor wants donors to know, from what the needle really feels like to what you should eat afterward.

In the Las Vegas shooting on Sunday night, at least 58 people were killed, and more than 400 others were transported to hospitals. Early this morning, the Las Vegas Police Department tweeted about the need for local blood donors, reminding us that in the wake of this tragedy—as well as the devastation wrought by Hurricanes Maria, Irma, and Harvey—helping out can be as simple as rolling up a sleeve. Last summer, Health spoke with Justin Kreuter, MD, medical director of the Mayo Clinic Blood Donor Center in Rochester, Minnesota. Here's what he wants potential donors to know:

Eligibility is always changing

The Red Cross maintains an alphabetical list of eligibility criteria for potential donors—from acupuncture (thumbs up) to Zika (thumbs down)—and can give you the latest information on whether or not you’re good to give.

The FDA regulates donor blood just as aggressively as it regulates drugs

“It takes a lot of money to do the infectious-disease testing that we do [on donor blood], and when we create blood products out of the donation, that’s done to the same standards as any drug manufactured in this country. The FDA holds us to those same standards, so it’s a very high level of quality and also resources that are invested,” Dr. Kreuter explains. “These tests and high standards are what’s keeping the blood supply safe, so that if my wife or one of my daughters needs a blood transfusion, I can feel assured that I can just sit at their bedside and hold their hand rather than worry about what that might result [in] for them later down the road.”

You’ll get a mini-physical before you donate

The flip side of donor blood screening (which ensures that it’s safe for the eventual recipient) is confirming the donor’s health (which ensures that the blood draw won’t have a negative effect on them). “We check blood pressure and pulse, we do a pinprick to check red blood cells to make sure they’re safe—we don’t want to make our donors iron deficient,” Dr. Kreuter says. He makes no specific suggestions about what you eat and drink prior to donation; just be sure you have breakfast and lunch under your belt, and take it easy on caffeine. “We all live on our daily espressos and whatnot, but we see donors who show up and haven’t eaten [meals] and they’ve only been drinking coffee, and they’re quite dehydrated. When you donate you’re losing circulating fluid, so the water that you drink before and after your donation is important.”

You’ll hardly feel a thing—seriously

The needles used to collect blood are a bit larger than those you’d encounter when, say, receiving a flu shot, but the so-called ‘small pinch’ you feel at insertion is, truly, no big deal. “What we feel [at the start of a blood draw] is just on the surface of our skin. These needles have silicone on them, they’re made to glide and be quite comfortable. After that initial stick, you’re not going to feel anything,” Dr. Kreuter says. If needles give you the shivers, look away for the quarter-second in which yours is placed; then ask a staffer to cover up the insertion site for you. Since the "tough" part is already over, you can lie back and spend the next eight to 10 minutes zoning out.

It’s okay to have a cookie after you donate

“What’s healthy is to keep a balanced diet as you go forward in the day [after your donation],” Dr. Kreuter says. “We tend to stock our canteen area with things like water and juice and then salty snacks, because salt helps you retain a little more of the [water] volume that you’ve lost through donation. The cookies are there because [they’re] something the donor culture has grown up in—maybe not the healthiest option, but certainly an expectation. Believe it or not, I have meetings about cookies. I’ve seen shirts before that say ‘I donate for the cookies.’” Bottom line: Rewarding yourself with a treat isn’t going to do any harm, provided that you indulge in moderation.

Your blood could save patients who haven’t even entered the world yet

Though many of us are reminded of the importance of blood donation when tragedies happen, much of what we give does the quiet work of saving people who’ll never show up on the news. Since the need for blood doesn’t go away, the best way to save lives is to contribute regularly. “At Mayo, about 15% to 20% of our blood is going to trauma patients and being used in our ER; a lot of our blood gets used supporting patients through life-saving cardiac or cancer surgeries. Cancer patients [also need blood]—chemotherapy knocks down their ability to make their own red blood cells and platelets—and folks who have medical conditions like autoimmune diseases also need transfusions.”

Donations flow to delivery rooms, too: “If anemia is significant enough in utero we transfuse during pregnancy and sometimes immediately after delivery,” Dr. Kreuter explains. “A lot of kids need blood in the first couple of minutes of life. Sometimes with newborn babies an emergency platelet transfusion in the first few moments of life is absolutely necessary; in their situation the newborn brain is so delicate and fragile that having these platelets immediately available is the name of the game in order to prevent bleeding into their brains, which results in long-term disabilities.”

Note that platelets have a shelf life of just five days, while whole blood can be stored for up to six weeks. The immediate need for platelets—and platelet donors—is constant.

Donating your voice is vital, too

Those "Be nice to me, I gave blood today!" stickers aren’t merely a cute (and justified) humblebrag: They’re also a benevolent form of peer pressure, not unlike the "I voted" stickers we earn and wear on election days. “Hearing about blood donation from a friend or colleague is very motivating in getting [potential first-timers] to think about taking that next step,” Dr. Kreuter says. “Our donor population [in Rochester] has an older average age, and we’re trying to reach out to the younger generation to start having the same blood donation habits.”

Think about it this way: Taking your kids to see you strengthen your community’s heartbeat at a blood center is just as important as bringing them with you to the voting booth. Donate visibly, donate vocally, and donate as often as you can.